At Home in the Cold

This nonfiction article is written for use with upper-elementary students (grades 4-5). Modified versions are available for students in grades K-1 and grades 2-3, or any student needing a simplified version. As always, consider the reading level and needs of your students when selecting a version for classroom use.

At each grade level, the article is available in three forms. Printable pdf files allow you to print this story in either text-only or a foldable book format. A partnership with Content Clips has allowed us to create electronic versions of the articles. Your students can read along as they listen to the text – a wonderful way to support struggling readers! Readers Theater scripts and related activities provide suggestions for integrating this story with your science and literacy instruction.

Interested in other nonfiction articles for your students? Browse all twenty sets from the Beyond Penguins and Polar Bears collection on our Stories for Students page!

AT HOME IN THE COLD

Imagine that you are in the Arctic or Antarctica. What do you see? You might have pictured either the Arctic Ocean or the Southern Ocean, which surrounds Antarctica. These oceans are cold, but full of life. Many of the living things in polar oceans actually depend on the cold water all around.

What kinds of animals live in these cold oceans? Penguins, whales, and walruses, to name a few. Like you, these animals produce heat all the time. Their bodies turn energy from food into heat. We say that these types of animals are warm-blooded because they make their own heat. That heat constantly escapes their bodies.

This heat loss is a problem on land, but it is a real emergency in water. If you were plunged into the icy cold waters of the polar regions, you would quickly lose all your body heat. Yet many warm-blooded creatures are able to survive. How?

The answer is insulation. These animals’ bodies have a thick layer of fat called blubber. Blubber helps hold in the heat even in the coldest of waters.

The system works so well that many of these creatures depend on the water to survive. If a whale is stranded on land, its blubber may cause it to overheat. Air can’t remove heat fast enough to keep the creature cool. The whale may die from its own internal heat.

In water, though, whales, walruses, and penguins are right at home. Not too cold, not too warm, their bodies are perfectly adapted for the chilly waters all around them.

While warm-blooded animals need blubber to live in the polar waters, how could cold-blooded animals like snakes, turtles, salamanders, and fish survive? These creatures don’t make their own heat. Instead they depend on the environment to warm them up.

Indeed, it is rare to find any of these kinds of animals in the polar regions. On land, that is. Yet the waters near the poles are full of many different kinds of cold-blooded fish.

What adaptations allow fish to survive in these cold waters? Some species, such as Arctic cod, actually have antifreeze proteins in their blood. The antifreeze proteins keep the fish’s blood from freezing solid, even as its body temperature drops. This fish antifreeze is so good that food engineers use it in – are you ready for this? – ice cream!

If ice cream freezes improperly, large ice crystals can ruin its texture. Adding fish antifreeze to the ice cream can keep it tasting smooth, creamy, and delicious. Yum!

Other fish have even stranger adaptations than the Arctic cod. Consider the strange case of the crocodile icefish. All fish have blood. For most fish, red blood cells carry oxygen through their bodies. Their cells need oxygen to survive. In very cold water, oxygen is plentiful. This is because the colder the water gets, the more oxygen the water can hold.

The crocodile icefish lives the cold waters of the Southern Ocean. This fish has blood, pumped by an oversized heart. But the blood isn’t red! Instead, the crocodile icefish’s blood is completely clear. Its blood looks just like water. In fact, the icefish’s blood is seawater, with only a few white blood cells mixed in. The red blood cells are missing.

Blood really is thicker than water. As blood gets cold, it becomes sluggish. Think of pancake syrup that’s been kept in the refrigerator. A fish with thick, cold, sluggish blood might have a hard time surviving in the Southern Ocean. The crocodile icefish doesn’t have this problem because it doesn’t have any red blood cells.

But how does the icefish live without red blood cells? The cold seawater is so rich in oxygen that the icefish doesn’t need them. Instead the fish pumps seawater through its body. The icefish gets all the oxygen it needs right from the cold water. The icefish doesn’t just tolerate cold water. It actually depends on cold water to stay alive.

Most of us live where the weather is warmer. We enjoy the feel of the sunlight on our skin. We like the warmth that comes with long summer days. But for animals adapted to colder climates, their icy world isn’t just home; it’s the only place they can survive.

Glossary

adaptations – structures or features of an organism that help it meet a particular need in its natural habitat

antifreeze – a chemical that keeps a liquid from freezing

blubber – a layer of fat that helps ocean animals stay warm

cold-blooded – describes an animal whose body temperature changes as the temperature of its surroundings changes

insulation – a material that does not conduct heat well

warm-blooded – describes an animal whose body stays the same temperature regardless of the temperature of its surroundings

Flesch-Kincaid Reading Level = 5.0

Modified versions of this text are available for grades K-1 (Flesch-Kincaid Reading Level = 1.3) and grades 2-3 (Flesch-Kincaid Reading Level = 3.4). See below for links to all three versions in text, book, and electronic book forms.

Printable Files

You can put this book together a couple of different ways. You can print out the pages, cut them in half and then order the pages back to front. Fold the stack in half and then staple the spine of the book. Pairs of pages can then be stapled or glued along the right edge.

You can also assemble the book as a foldable book.

To assemble the book this way, print the four pages and align the document pages so that the following book page numbers are in the lower right-hand corner: front page, page 6, page 2, and page 4. (The cover page should be on top and page 4 on the bottom.) Set your copier to copy single pages into double pages and run the four document pages in the order specified. Cut along the dotted line in the center of the double-sided page, place the book pages in order, fold, and staple along the spine.

Electronic Books

A partnership with Content Clips has allowed us to provide electronic versions of our expository articles. Students can listen to the articles as they read along on the screen.

These versions require Adobe Flash to view. If you don’t have Flash, you can download it for free from the Adobe web site. You will also need to turn off your pop-up blocker to use Content Clips.

In each book, the play button (in the top right-hand corner) will play an audio file of the text on that page, while the icon in thebottom right-hand corner will turn to the next page.

Please note that the audio files take a moment to load on each page. Once the file has been loaded, a play button will appear in the top right-hand corner of the page. To minimize the delay on each page, you can open the file and read through the article first. Once each page’s audio has loaded, it remains loaded until you close the browser window. By preparing the article ahead of time, you can have students start at the beginning of the book and read without delays.

We’ve also created a literacy set that includes all of the illustrated and electronic books in one convenient location!

Content Clips is an interactive web environment designed to help K-12 teachers supplement their curriculum with compelling online resources and activities. By creating a free account, you can save resources and activities (such as the electronic books and set) to your own collection. You can also create your own interactive activities to use in your classroom. If you follow the links to the electronic books listed above, you will enter the site as a guest and will not be able to save them to your own collection. If you wish to save these stories in your own collection, create an account, login, and then search for “At Home in the Cold.”

READERS THEATER SCRIPTS

Readers Theater is an excellent way to differentiate instruction, support struggling readers, and help all students master science content, improve fluency, and enhance comprehension. For more information on Readers Theater, please see “Creating Readers Theater Scripts from Informational Text.”

We’ve created Readers Theater scripts for students in grades K-1, 2-3, and 4-5 from this month’s Feature Story:.

Want to create other polar RT scripts? Browse informational text about a variety of polar-related science topics on our Stories for Students page!

RELATED ACTIVITES

Polar Bears: Keeping Warm at the Arctic (Grades K-2)
Students learn about the polar bear’s body coverings and how the coverings help the bear survive in the Arctic climate. This lesson can be generalized to apply to other marine mammals, such as whales and seals, as well as to penguins.

Polar Bears and Their Adaptations (Grades 3-5)
Students explore how a polar bear’s body adapts to survive in the harsh environment in which the bear lives. This lesson can be generalized to apply to other marine mammals, such as whales and seals, and to penguins.

Life in a Deep Freeze (Grades 3-5)
This article from the children’s magazine National Geographic Explorer describes the various adaptations that keep animals warm in the cold Arctic environment.

Copyright December 2009 – The Ohio State University. This material is based upon work supported by the National Science Foundation under Grant No. 0733024. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.This work is licensed under an Attribution-ShareAlike 3.0 Unported Creative Commons license.